JP2539855B2 - Nonlinear optical material and nonlinear optical element using the same - Google Patents

Description

The present invention relates to a nonlinear optical material and a nonlinear optical element using the same, and a nonlinear optical material preferably used in the field of optoelectronics and a nonlinear optical element using the same. Regarding

<Problems to be Solved by Prior Art and Invention> The non-linear optical effect is a phenomenon in which when light enters a medium, polarization proportional to the second-order or higher-order term of the electric field of the light occurs, A non-linear optical effect appears remarkably under a strong electric field such as light. This nonlinear optical effect enables generation of the second harmonic, Kerr effect, optical bistability, etc. Especially, the second-order nonlinear optical effect occurring in proportion to the square of the electric field of light is an optical wavelength conversion element or an optical modulation element. Since it can be applied to non-linear optical elements such as the above, which can be applied to elements that promise the development of the optoelectronics field, they have received much attention.

The materials that make up these devices are currently KH ₂ PO ₄
Only some inorganic materials such as (KDP) are in practical use. However, the non-linear optical constants of these inorganic materials are small, and therefore extremely high voltage or extremely high light intensity is required for the operation of the device. Therefore, the demand for materials having large nonlinear optical constants is extremely strong, and various materials have been searched for. Among inorganic materials, lithium niobate (LiNbO ₃ ) has the largest nonlinear optical constant, but lithium niobate causes a partial change in the refractive index when irradiated with a strong laser beam, and is easily exposed to light. It has the drawback of being damaged and has not yet been put to practical use.

Recently, it has been found that organic materials have much higher nonlinear optical properties than inorganic materials, such as 2-methyl-4-nitroaniline (MNA).
As typified by, a material having a π-electron system, an electron-donating group and an electron-withdrawing group in the molecule, and an extremely large nonlinear optical constant is drawing attention. But,
In order to obtain the second-order nonlinear optical effect, it is necessary that the crystal structure does not have an inversion symmetry center, and it is ideal that the molecules in the crystal are arranged in one direction. It is extremely difficult to control the crystal structure of a compound having an optical constant β (hereinafter referred to as a non-linear optical constant β) larger than that of MNA in a molecular state, that is, a compound having a larger permanent dipole moment or a larger π electron system. It has been difficult to report an organic compound having a second-order nonlinear optical effect higher than that of MNA, and thus, a nonlinear optical material and a nonlinear optical element having a higher efficiency than MNA have not been known.

<Purpose> The present invention has been made in view of the above problems, and an object thereof is to provide an organic nonlinear optical material having a high nonlinear optical effect and a nonlinear optical element using the same.

<Means and Actions for Solving Problems> The nonlinear optical material of the first invention is characterized by containing at least a compound represented by the following general formula [I].

(In the formula, R represents a hydrogen atom, an alkyl group or a phenyl group which may have a substituent, and Z represents a hydrogen atom, a carboxy group, an alkoxycarbonyl group or a carbamoyl which may have a substituent. In organic non-linear optical materials, in order to increase the non-linear optical constant β, it is necessary for the electron transfer in the molecule to proceed smoothly when polarization occurs due to the electric field of light. According to the first aspect of the present invention, the compound represented by the general formula [I] has a cyano group having a large electron-withdrawing property and a carbazole skeleton bonded by a conjugated bond.
Electrons largely move with the transition of electrons, the nonlinear optical constant β at the molecular level is large, and a remarkable nonlinear optical effect is exhibited.

In the compound represented by the above general formula [I],
R is an alkyl group having 1 to 15 carbon atoms, a phenyl group which may have an alkoxy group having 1 to 15 carbon atoms, Z is an alkoxycarbonyl group having 1 to 15 carbon atoms in the alkoxy moiety,
A compound which is a cyano group, in which R is an alkyl group having 1 to 6 carbon atoms, a phenyl group which may have an alkoxy group having 1 to 6 carbon atoms, and Z is 1 carbon atom in the alkoxy portion.
The compound having an alkoxycarbonyl group or a cyano group of ˜6 has a large electron mobility and is preferable for increasing the nonlinear optical constant β.

Furthermore, the compound represented by the general formula [I] is 3-
(2-Cyano-2-methoxycarbonyl) vinyl-9-
Methylcarbazole, 3- (2-cyano-2-ethoxycarbonyl) vinyl-9-methylcarbazole, 3-
(2-Cyano-2-methoxycarbonyl) vinyl-9-
Ethylcarbazole, 3- (2-cyano-2-ethoxycarbonyl) vinyl-9-ethylcarbazole, 3-
(2-Cyano-2-ethoxycarbonyl) vinyl-9-
(4-methoxyphenyl) carbazole, 3- (2,2-
A non-linear optical material selected from dicyano) vinyl-9-methylcarbazole, especially a non-linear optical material composed of a single component crystal of the above compound, has a larger non-linear optical constant and is preferable as the non-linear optical material.

The nonlinear optical element of the second invention is a nonlinear optical element having an optical waveguide section, and the optical waveguide section is composed of a nonlinear optical material containing at least the compound represented by the general formula [I]. It is characterized by being.

According to the nonlinear optical element having the above-described configuration, the optical waveguide portion is made of the nonlinear optical material containing at least the compound represented by the general formula [I] having a large nonlinear optical constant. It is possible to obtain a second-order non-linear optical element having a large intensity, it is possible to separate a high intensity second harmonic even with a laser beam having a weak intensity, and it is possible to efficiently produce an electro-optical effect even with a small voltage change.

 Hereinafter, the first invention will be described in detail.

In the compound represented by the above general formula [I], the alkyl group in the substituent R is, for example, methyl, ethyl, propyl, isopropyl, butyl, tert-butyl,
Examples thereof include alkyl groups such as pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl and pentadecyl. Among the above-mentioned alkyl groups, a straight chain or branched chain alkyl group having 1 to 15 carbon atoms, particularly 1 to 6 carbon atoms is preferable, and among them, a methyl group and an ethyl group are preferable.

As the substituent of the phenyl group which may have a substituent, the above-mentioned alkyl group; hydroxy group; hydroxyalkyl group such as methylol, 2-hydroxyethyl, 3-hydroxypropyl; methoxy, ethoxy, propoxy, iso Propoxy, butoxy, isobutoxy, te
rt-Butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, tridecyloxy, tetradecyloxy, pentadecyloxy and other alkoxy groups; mercapto group; methylthio, ethylthio, Alkylthio groups such as propylthio, butylthio and hexylthio; aralkylthio or arylthio groups which may have a substituent such as benzylthio and phenylthio; amino, methylamino, ethylamino, propylamino, isopropylamino, butylamino, hexylamino, An amino group which may have an alkyl group such as dimethylamino, methylethylamino, diethylamino, dipropylamino, dibutylamino; benzylamino,
Examples thereof include aralkylamino groups such as benzhydryl and tritylamino; arylamino groups such as phenylamino and diphenylamino; halogen atoms such as fluorine, chlorine, bromine and iodine.

Among the substituents of the phenyl group, those selected from the group consisting of an alkyl group, a hydroxy group, an alkoxy group, a mercapto group, an alkylthio group, and an amino group which may have an alkyl group are preferable, and the number of carbon atoms is 1 to 1. 15, especially an alkoxy group having 1 to 6 carbon atoms, of which a methoxy group and an ethoxy group are preferable. Further, the above-mentioned substituent may be substituted at an appropriate position on the benzene ring, but is preferably substituted at the p-position in which electron transfer accompanying electron transition is large. Further, it is sufficient that at least one of the above substituents substitutes on the benzene ring.

Among the substituents Z, the alkoxycarbonyl group is
For example, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, tert-butoxycarbonyl, hexyloxycarbonyl, heptyloxycarbonyl, octyloxycarbonyl, nonyloxycarbonyl, decyloxycarbonyl, undecyloxy. Examples thereof include alkoxycarbonyl groups such as carbonyl, dodecyloxycarbonyl, tridecyloxycarbonyl, tetradecyloxycarbonyl and pentadecyloxycarbonyl.

As the carbamoyl group which may have a substituent,
Examples thereof include carbamoyl, methylcarbamoyl, dimethylcarbamoyl, ethylcarbamoyl, propylcarbamoyl, phenylcarbamoyl and benzylcarbamoyl.

Of the above substituents Z, the alkoxy part has 1 to 1 carbon atoms.
5, especially a lower alkoxycarbonyl group having 1 to 6 carbon atoms,
Of these, a methoxycarbonyl group, an ethoxycarbonyl group and a cyano group are preferable.

In the compound represented by the above general formula [I], the substituents R and Z can be appropriately selected depending on the strength of the electron withdrawing property, the electron donating property and the like of each substituent. ~ 6 alkyl group, a phenyl group optionally having an alkoxy group having 1 to 6 carbon atoms, particularly a group consisting of a methyl group, an ethyl group, or a phenyl group optionally having a methoxy group or an ethoxy group. Z is a group selected from
A compound in which is a group selected from the group consisting of an alkoxycarbonyl group having 1 to 6 carbon atoms in the alkoxy moiety and a cyano group, particularly a methoxycarbonyl group, an ethoxycarbonyl group or a cyano group, is polarized by an electric field such as light. In this case, the electron mobility is large, and the particularly large nonlinear optical constant β
And a preferable molecular structure and crystal structure as a nonlinear optical material.

In particular, the compound represented by the general formula [I] is 3-
(2-Cyano-2-methoxycarbonyl) vinyl-9-
Methylcarbazole, 3- (2-cyano-2-ethoxycarbonyl) vinyl-9-methylcarbazole, 3-
(2-Cyano-2-methoxycarbonyl) vinyl-9-
Ethylcarbazole, 3- (2-cyano-2-ethoxycarbonyl) vinyl-9-ethylcarbazole, 3-
(2-Cyano-2-ethoxycarbonyl) vinyl-9-
(4-methoxyphenyl) carbazole, 3- (2,2-
The non-linear optical material selected from dicyano) vinyl-9-methylcarbazole has a larger non-linear optical constant,
Preferred as a non-linear optical material.

The compound represented by the general formula [I] can be produced, for example, by a condensation reaction of the compound represented by the following general formula [II] and the compound represented by the following general formula [III].

(In the formula, R and Z are the same as above.) The compound represented by the general formula [II] and the general formula [III]
The reaction for obtaining the compound represented by the general formula [I] from the compound represented by is usually carried out in an organic solvent, and any solvent can be used as long as it does not adversely influence the reaction. , For example, aliphatic or alicyclic hydrocarbons such as n-hexane, n-octane and cyclohexane, aromatic hydrocarbons such as benzene, toluene and xylene, alcohols such as methanol, ethanol and propanol, acetone and methyl ethyl ketone. Ketones, etc.
Examples thereof include ethers such as diethyl ether, tetrahydrofuran and dioxane, acetonitrile, dimethylformamide, dimethylsulfoxide, hexamethylphosphoric triamide and the like. The reaction is usually carried out at room temperature or under heating to reflux, and the reaction is completed in about several hours to 48 hours. After completion of the reaction, the reaction mixture can be concentrated and easily separated and purified by a conventional means such as recrystallization, solvent extraction, column chromatography and the like.

The nonlinear optical material containing at least the compound represented by the general formula [I] may be a single component crystal of the compound represented by the general formula [I], and is represented by the general formula [I]. It may be a mixed crystal or a mixed solid composed of a mixture of the compound and another nonlinear optical material or a liquid crystalline polymer.

The single-component crystal of the compound represented by the above general formula [I] has a large nonlinear optical constant β even in the crystalline state, and
It has a non-linear optical effect. Further, in the above-mentioned mixed crystal or mixed solid, the molecular arrangement in the crystal can be controlled to provide a nonlinear optical material having a large second-order nonlinear optical effect.

As the other non-linear optical material, various organic non-linear optical materials are used, but a material having a large non-linear optical constant, for example, a second-order non-linear optical constant β of 5 × 10 5 is used.
-Compounds of ^-30 esu or more are used. As such an organic nonlinear optical material, a compound having an electron-withdrawing group and an electron-donating group in the molecule, for example, MNA, 1-methoxy-4- (4-nitrobenzylideneamino) benzene, 1-methoxy-4- (4-nitrobenzylideneamino) benzene, Methyl-4- (4-nitrobenzylideneamino) benzene, 1-ethyl-4- (4-nitrobenzylideneamino) benzene, 1-propyl-4- (4-nitrobenzylideneamino) benzene, 1-butyl-4-
(4-Nitrobenzylideneamino) benzene, 1- (4
Schiff base type compounds such as -nitrobenzylideneamino) -4-hexylbenzene, 1- (4-nitrobenzylideneamino) -4-octylbenzene, 1-ethyl-4- (4-cyanobenzylideneamino) benzene; 1-methyl Aminoanthraquinone, 2-methylaminoanthraquinone, 1,4-diamino-6-ethoxycarbonylanthraquinone, 1,4-diamino-2- (1-pyrrolidinyl)
Anthraquinone derivatives such as anthraquinone; ethyl 1,
Dithiol derivatives such as 3-dithiol-2-ylidene cyanoacetate and ethyl 4-methyl-1,3-dithiol-2-ylidene cyanoacetate; β, β-dicyano-4-methoxystyrene, β, β-dicyano- Styrene derivatives such as 4-methylstyrene; 2-bromo-4-nitro-N, N-dimethylaniline; 4-N, N-dimethylamino-
Examples include 4'-nitrostilbene; 2-ethylamino-1,3,4-thiadiazole and the like. The mixing ratio of the compound represented by the general formula [I] and the organic nonlinear optical material described above is such that desired optical properties and physical properties of the compound (for example, melting point,
It can be appropriately selected depending on the solubility, λ max, etc.).

A crystal consisting of a single component of the compound represented by the general formula [I] or a mixture crystal of the compound represented by the general formula [I] and the other non-linear optical material is, for example, ] A compound represented by the formula [1] is melted by heating and then cooled to be crystallized; a method in which the compound is dissolved in a suitable solvent at a suitable temperature, and then the solvent is removed or the temperature is lowered to crystallize; Examples thereof include a method using a vapor deposition method such as vacuum deposition and molecular beam epitaxy. The first crystallization method may be a melt solidification method in which, when crystallizing, the melt of the compound represented by the general formula [I] is crystallized in a heating furnace having a temperature gradient. The organic solvent used in the second crystallization method may be a polar solvent such as methanol or ethanol having a hydroxy group capable of hydrogen bonding, a polar solvent such as acetonitrile, ethyl acetate, diethyl ether or tetrahydrofuran, or benzene. It may be a nonpolar solvent or a small polar solvent such as toluene, or cyclohexane. At this time, if necessary, a solvent having an asymmetric carbon, for example, (R) -2-
Crystals may be obtained from a solvent having an asymmetric carbon such as butanol.

Examples of the liquid crystalline polymer include a side chain type liquid crystalline polymer having a mesogen group in the side chain, a side chain type polyacrylate type liquid crystal polymer, a side chain type polysiloxane type liquid crystal polymer and the like. By forming a solid mixture with the liquid crystalline polymer, the molecular orientation of the compound represented by the general formula [I] can be controlled by utilizing the molecular orientation of the liquid crystalline polymer.

In addition, the solid mixture of the compound represented by the general formula [I] and the liquid crystalline polymer is gradually melted after the mixture of the compound represented by the general formula [I] and the liquid crystalline polymer is melted. It is obtained by cooling to a liquid crystal state, then applying an electric field or a magnetic field, and cooling and solidifying in that state. Since the liquid crystalline polymer is solidified in the aligned state by the application of an electric field or a magnetic field, it is possible to obtain a solid in a molecular arrangement state in which the compound represented by the general formula [I] does not have a center of symmetry. In the mixture of the compound represented by the general formula [I] and the liquid crystalline polymer, the mixing ratio of the respective components should be such that the compound represented by the general formula [I] can be in a molecularly oriented solid state. It is not particularly limited, and can be appropriately selected depending on the properties of the compound represented by the general formula [I] and the liquid crystalline polymer used (for example, phase transition temperature, etc.). The content of the represented compound is about 2 to 60% by weight. In addition, in the said substituent R and Z, it is C2-C15, especially the C2-C15 alkyl group or alkoxy group, or the C2-C15 of an alkoxy part, especially C4.
The compound having a substituent of ˜15 has excellent compatibility with the above-mentioned liquid crystalline polymer, so that it has an advantage that the molecular arrangement in the mixture solid can be further controlled and the film can be formed into a thin film.

As described above, the nonlinear optical material containing at least the compound represented by the general formula [I] has a large nonlinear optical constant β and has a remarkable nonlinear optical effect. Therefore,
Materials for nonlinear optical elements used in the field of optoelectronics, for example, materials for optical wavelength conversion elements and materials for optical modulation elements such as phase modulation elements, amplitude modulation elements, frequency modulation elements, pulse modulation elements, polarization plane modulation elements Is suitable as Further, as the above-mentioned nonlinear optical material, the crystal itself of the compound represented by the general formula [I] can be used as an optical wavelength conversion element, but a waveguide type optical wavelength conversion element using the nonlinear optical material as an optical waveguide is used. May be [J.Zyss, JM
olecular Electronics 1, 25 (1985) etc.]. By using a waveguide type optical wavelength conversion element, the light is confined in the waveguide, so the optical power density is increased, and the interaction length can be lengthened, resulting in higher efficiency and further mode Phase matching using dispersion is also possible.

<Embodiment> The first embodiment will be described below with reference to the accompanying drawings showing an embodiment.
A non-linear optical element using the non-linear optical material of the invention will be described in detail.

FIG. 1 shows an embodiment of the optical wavelength conversion element of the present invention,
1 is a schematic view of an optical fiber type optical wavelength conversion element as a second harmonic generation element, showing a core (1) made of a nonlinear optical material (hereinafter referred to as a nonlinear medium) containing at least a compound represented by the general formula [I]. ) Has a structure covered with a cladding (2) made of a medium such as glass (hereinafter, referred to as an isotropic medium) that does not exhibit a second-order nonlinear optical effect,
In the figure, the alternate long and short dash line indicates the fundamental wave of the incident light, and the alternate long and two short dashes line indicates the second harmonic. Light such as laser light is condensed by a lens or the like and is incident on the core (1) from one end surface of the light wavelength conversion element. The nonlinear medium forming the core (1) is large 2
Since the following nonlinear optical effect is exhibited, the light emitted from the other end surface of the core (1) includes a fundamental wave and a second harmonic wave, and the second harmonic wave is extracted by separating the light with a spectral means such as a prism or a filter. Be done.

2 and 3 are schematic diagrams showing other embodiments of the light wavelength conversion element, respectively, and in the drawings, the alternate long and short dash line and the alternate long and two short dashes line have the same meanings as in FIG. 1, respectively.

In the optical wavelength conversion element shown in FIG. 2, an optical waveguide section (2) made of a nonlinear medium is formed on a substrate (22) made of an isotropic medium.
1) is formed, and in the optical wavelength conversion element shown in FIG. 3, a substrate (32) made of an isotropic medium,
An optical waveguide portion (31) made of a non-linear medium is formed between it and a top layer (33) also made of an isotropic medium. The light wavelength conversion element described above is used in the same manner as the light wavelength conversion element shown in FIG.

Further, as the light modulation element, a device of a form conventionally used can be used. FIG. 4 shows, as an example thereof, a schematic view of an optical waveguide type optical modulation element of a lateral type operation as a phase modulation element, in which a substrate (4
A waveguide (41) made of a non-linear medium is provided in the inside of 2), and two electrodes (4) are provided through the waveguide (41).
3) are provided at opposite positions along the length direction, and an electric field is formed by applying a voltage between the electrodes (43). In the above element, when the light incident from one end of the waveguide section (41) in the length direction passes through the waveguide section (41) and is emitted from the other end surface, a nonlinear medium forming the waveguide section (41) When the refractive index of the light changes, the phase of the emitted light also changes. Since the refractive index of the non-linear medium changes depending on the applied voltage, by changing the applied voltage between the electrodes (43),
The phase of the emitted light can be modulated.

In the optical wavelength conversion element shown in FIGS. 1 to 4, the core (1) and the optical waveguides (21) (31) (41) are formed, for example, by using a nonlinear medium raw material and an isotropic medium, respectively. In a capillary consisting of, on a waveguide substrate made of an isotropic medium, or between waveguide substrates made of an isotropic medium, heating and melting, then slowly cooling to precipitate crystals, and vacuum deposition method on the substrate , A method of precipitating a crystal by a high frequency sputtering method or the like, and
A method of precipitating crystals from the solution in which the non-linear medium raw material is dissolved in an appropriate organic solvent in the above-mentioned capillary, on the substrate or between the substrates may be used. Further, in some cases, after processing the portion of the capillary, on or between the substrates, which is to be the contact interface with the nonlinear medium with the alignment treatment material, the nonlinear medium is precipitated and crystal grown to form an optical wavelength conversion element or the like. May be. As the alignment treatment material, an inorganic salt and an organic salt (for example, hexadecyltrimethylammonium bromide), a thin film made of an appropriate polymer (for example, polyamide), a metal complex, a metal thin film (for example, an obliquely evaporated gold thin film) Etc.) are exemplified.

The non-linear optical element of the present invention is not limited to the above-mentioned embodiment, and the light modulation element may be a vertical operation optical waveguide type light modulation element capable of amplitude modulation, or a non-linear crystal such as a crystal. It is also possible to adopt a form in which a voltage is directly applied to the medium itself. In the light modulation element, the electric field application direction for efficiently performing the phase modulation differs depending on the symmetry of the nonlinear medium, the direction of the crystal axis, and the like. Therefore, it is preferable to appropriately change the electrode configuration based on these.

Hereinafter, the present invention will be described in more detail based on specific examples.

Example 1 To 10 ml of benzene, 0.4 g of ethyl cyanoacetate was added, and 0.1 ml of piperidine was further added to prepare an ethyl cyanoacetate solution. Also, 3-formyl-9 is added to 10 ml of benzene.
Dissolve 0.75 g of ethylcarbazole, add the resulting solution to the ethyl cyanoacetate solution and stir at room temperature for 2 hours. After completion of the reaction, the solvent was distilled off, the residue was dried, and the produced yellow solid was recrystallized from benzene to give the desired compound 3- (2-cyano-2-ethoxycarbonyl).
0.88 g (yield 83%) of vinyl-9-ethylcarbazole is obtained.

Melting point: 139 to 140 ° C IR (KBr) νmax / cm ^-1 : 3020, 2240, 1725, 1580 ¹ H-NMR (CDCl ₃ ) δ: 1.42 (3H, t), 1.48 (3H, t), 4.39 (2H) , q), 4.41 (2
H, q), 7.36 (1H, t), 7.46 (1H, d), 7.47 (1H, d),
7.54 (1H, t), 8.17 (1H, d), 8.24 (1H, q), 8.43 (1
H, s), 8.76 (1H, d) Mass spectrum (70e V) m / e 318 When the obtained crystal was irradiated with Nd: YAG laser light having a wavelength of 1.064 μm, light having a wavelength of 0.532 μm, which was the second harmonic, was observed.

Specific Example 2 In place of 3-formyl-9-ethylcarbazole of Specific Example 1, 3-formyl-9-methylcarbazole was used, and the target compound 3- was prepared in the same manner as in Specific Example 1 above.
(2-Cyano-2-ethoxycarbonyl) vinyl-9-
0.80 g (77% yield) of methylcarbazole is obtained.

Melting point: 196 to 197 ° C IR (KBr) νmax / cm ⁻¹ : 3020, 2240, 1725, 1580 ¹ H-NMR (CDCl ₃ ) δ: 1.42 (3H, t), 3.91 (3H, s), 4.40 (2H) , q), 7.34 (1
H, t), 7.46 (1H, d), 7.47 (1H, d), 7.56 (1H, t),
8.16 (1H, d), 8.24 (1H, q), 8.77 (1H, d) Mass spectrum (70e V) m / e 304 When the obtained crystal was irradiated with Nd: YAG laser light having a wavelength of 1.064 μm, light having a wavelength of 0.532 μm, which was the second harmonic, was observed.

Example 3 To 10 ml of benzene, 0.3 g of malonnitrile was added, and then 0.1 ml of pyridine was added to prepare a malonnitrile solution. Further, 0.65 g of 3-formyl-9-methylcarbazole was dissolved in 10 ml of benzene, the resulting solution was added to the malonnitrile solution, and the mixture was stirred at a temperature of 40 ° C. for 3 hours. After completion of the reaction, the solvent was distilled off and the resulting yellow solid was recrystallized from ethanol to give 0.6 g of the target compound 3- (2,2-dicyano) vinyl-9-methylcarbazole (yield 60%). To get

Melting point: 197 to 198.5 ° C IR (KBr) νmax / cm ^-1 : 2210, 1575, 1550 ¹ H-NMR (CDCl ₃ ) δ: 3.93 (3H, s), 7.36 (1H, t), 7.48 (2H, d) ), 7.59 (1
H, t), 7.87 (1H, s), 8.11 (1H, q), 8.14 (1H, d),
8.65 (1H, d) Mass spectrum (70e V) m / e 257 When the obtained crystal was irradiated with Nd: YAG laser light having a wavelength of 1.064 μm, light having a wavelength of 0.532 μm, which was the second harmonic, was observed.

Concrete Example 4 After melting the crystal obtained in Concrete Example 1 by heating, a glass capillary (inner diameter 5 to 10 μm, outer diameter 0.5 to 1 mm, length 2 to 3 c)
After injecting into m) by utilizing a capillary phenomenon, crystals were grown in a Bridgman furnace to fabricate a light wavelength conversion element. When Nd: YAG laser light with a wavelength of 1.064 μm was irradiated from one end face of this element, generation of a second harmonic with a wavelength of 0.532 μm was observed from the other end face.

Specific Examples 5 and 6 The crystals obtained in Specific Examples 2 and 3 were heated and melted, and then injected into a glass capillary (inner diameter 5 to 10 μm, outer diameter 0.5 to 1 mm, length 2 to 3 cm) by utilizing capillary phenomenon. After that, a crystal was grown in a Bridgman furnace to fabricate a light wavelength conversion element. From one end face of this element, Nd: YA with a wavelength of 1.064 μm
When irradiated with G laser light, the wavelength is 0.532 μm from the other end surface.
The generation of the second harmonic of was observed.

<Effects of the Invention> As described above, according to the nonlinear optical material of the first invention, in the compound represented by the general formula [I], the cyano group having a large electron-withdrawing property and the carbazole skeleton are conjugated to each other. Therefore, in the nonlinear optical material containing at least the compound represented by the general formula [I], electron transfer rapidly occurs when polarization occurs due to an electric field such as light, and the nonlinear optical constant β is large. , Shows a remarkable nonlinear optical effect.

Further, according to the nonlinear optical element of the second invention, since the nonlinear optical material of the first invention is used, a second-order nonlinear optical element can be obtained, and even if the laser light with low light intensity is high in intensity, It is possible to separate the two harmonics, and it is possible to efficiently exhibit the electro-optical effect even with a small voltage change.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of a non-linear optical element as an optical wavelength conversion element, and FIGS. 2 and 3 are schematic views showing other embodiments of a non-linear optical element as an optical wavelength conversion element, respectively. 4 and 5 are schematic diagrams showing an embodiment of a non-linear optical element as a phase modulation element. (1) …… Core, (2) …… Clad, (21) (31)
(41) …… optical waveguide, (22) (32) (42) …… substrate,
(33) …… Top layer, (43) …… Electrode.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naota Uenishi 1-3-3 Shimaya, Konohana-ku, Osaka City, Osaka Prefecture Sumitomo Electric Industries, Ltd. Osaka Works (72) Inventor Norihiko Yasuda Shimaya, Konohana-ku, Osaka City, Osaka Prefecture 1-3-1 Sumitomo Electric Industries, Ltd. Osaka Works

Claims (15)

(57) [Claims] 1. A nonlinear optical material comprising at least a compound represented by the following general formula [I]. (In the formula, R represents a hydrogen atom, an alkyl group or a phenyl group which may have a substituent, and Z represents a hydrogen atom, a carboxy group, an alkoxycarbonyl group or a carbamoyl which may have a substituent. Group, cyano group) 2. A compound represented by the general formula [I]:
R is an alkyl group having 1 to 15 carbon atoms, a phenyl group which may have an alkoxy group having 1 to 15 carbon atoms, Z is an alkoxycarbonyl group having 1 to 15 carbon atoms in the alkoxy moiety,
The nonlinear optical material according to claim 1, which is a cyano group. 3. A compound represented by the general formula [I],
R is an alkyl group having 1 to 6 carbon atoms, a phenyl group optionally having an alkoxy group having 1 to 6 carbon atoms, and Z is an alkoxycarbonyl group having 1 to 6 carbon atoms in the alkoxy moiety or a cyano group. The nonlinear optical material according to claim 1 or 2. 4. A compound represented by the general formula [I] is 3-
(2-Cyano-2-methoxycarbonyl) vinyl-9-
The nonlinear optical material according to claim 1, which is methylcarbazole. 5. A compound represented by the general formula [I] is 3-
(2-Cyano-2-ethoxycarbonyl) vinyl-9-
The nonlinear optical material according to claim 1, which is methylcarbazole. 6. A compound represented by the general formula [I] is 3-
(2-Cyano-2-methoxycarbonyl) vinyl-9-
The nonlinear optical material according to claim 1, which is ethylcarbazole. 7. A compound represented by the general formula [I] is 3-
(2-Cyano-2-ethoxycarbonyl) vinyl-9-
The nonlinear optical material according to claim 1, which is ethylcarbazole. 8. A compound represented by the general formula [I] is 3-
(2-Cyano-2-ethoxycarbonyl) vinyl-9-
The nonlinear optical material according to claim 1, which is (4-methoxyphenyl) carbazole. 9. A compound represented by the general formula [I] is 3-
The nonlinear optical material according to claim 1, which is (2,2-dicyano) vinyl-9-methylcarbazole. 10. The nonlinear optical material according to claim 1, which is composed of a single-component crystal of a compound represented by the general formula [I]. 11. A non-linear optical element having an optical waveguide section, wherein the optical waveguide section is composed of a non-linear optical material containing at least a compound represented by the following general formula [I]. Non-linear optical element. (In the formula, R represents a hydrogen atom, an alkyl group or a phenyl group which may have a substituent, and Z represents a hydrogen atom, a carboxy group, an alkoxycarbonyl group or a carbamoyl which may have a substituent. Group, cyano group) 12. The non-linear optical element according to claim 11, wherein the non-linear optical element is composed of a core made of a non-linear optical material and a clad made of a medium that covers the core and does not exhibit a non-linear optical effect. Optical element. 13. The non-linear optical element according to claim 11, wherein the non-linear optical element comprises a substrate made of a medium exhibiting no non-linear optical effect and an optical waveguide section made of the non-linear optical material formed on the substrate. The nonlinear optical element described. 14. A non-linear optical element comprises a substrate made of a medium exhibiting no non-linear optical effect, a layer made of a medium not exhibiting non-linear optical effect, and a non-linear optical material formed between the substrate and the layer. 12. The nonlinear optical element according to claim 11, which is composed of an optical waveguide section. 15. A non-linear optical element comprising a substrate made of a medium that does not exhibit a non-linear optical effect, an optical waveguide section made of a non-linear optical material formed on the substrate, and an electrode for applying an electric field to the optical waveguide section. Claims as constituted above
Item 11. A non-linear optical element described in item 11.